What it means
سست شدن (sost shodan) means to go weak, to become limp, or to grow slack. Both components are pure Persian: سست (sost), from Middle Persian “sust,” meaning weak, loose, or lacking tension, and شدن (shodan), meaning to become. The phrase can describe a physical state, such as muscles giving out, a rope losing its tautness, or a grip loosening, and it can also describe a mental or moral state, such as resolve fading or discipline eroding. A close contrast is محکم شدن (mohkam shodan), meaning to become firm or strong, which sits at the opposite end of the same scale.
How to use it
- بعد از تب پاهام سست شده. (Ba’d az tab pâhâm sost shode.) “After the fever my legs have gone weak.”
- حس میکنم بدنم سست شده و انرژی ندارم. (Hes mikonam badanam sost shode va enerji nadâram.) “I feel my body has gone limp and I have no energy.”
- ارادهاش سست شده بود. (Erâde-ash sost shode bud.) “His willpower had grown slack.”
- طناب سست شده، باید محکمش کنی. (Tanâb sost shode, bâyad mohkamash koni.) “The rope has gone slack, you need to tighten it.”
Cultural note
In Persian moral and literary tradition, سستی (sosti), the noun form, is considered a serious character flaw alongside laziness (تنبلی, tanbalí). Classical Persian literature, from Sa’di’s Golestan to modern proverbs, warns against letting one’s resolve become سست. In everyday conversation the word is equally at home describing a physical symptom after illness as it is criticizing someone for giving up too easily, making it one of those words that bridges the physical and the ethical in a single term.